Glass cloth spotting material



Search Room E. C. PFEFFER, JR

GLASS CLOTH SPOTTING MATERIAL Filed June 14, 1943 2] MMM Qgzyaf'd ffffj'emff:

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Patented Dec. 7, 1948 Search Room GLASS CLOTH SPOTTING MATERIAL Edward C. Pfeffer, Jr., Troy, N. Y., assignor to Continental Can Company, Inc., New York, N. Y., a corporation of New York Application J une 14, 1943, Serial No. 490,804

In providing closures for containers of foodstui'l's and other materials, it has been a practice to provide a resilient material for establishing a rm seat and seal upon the container and to employ a lining material for preventing contact of the contents of the container with this resilient pad.

In the ordinary crown seal employed for glass beverage bottles and cans, for example, it has been the practice to employ a cork disk as a cushion pad within the closure cap, and to surface this disk with a thin layer of aluminum or otherl metal which is non-permeable to the beverage. Owing to existing diiiiculties, the employment of aluminum for this purpose is restricted, and it is desirable to provide a lining material which is cheap, strong, and capable of performing its sealing functions under the conditions of manufacture and employment.

Normal baking operations upon lacquers and enamels applied to the surface of metal cans and the like require a temperature of at least 375 degrees F. to bring the resin to a condition at which it has the necessary strength and cohesion, and the requisite chemical resistance against penetration or dissolution by many liquids, such as water. When it is sought to form such a sealing material by employing resin lacquers directly upon the cushion pad, the necessity of baking the resin ata high temperature, for preventing the development of oiT-avors in the contents of the container, creates difficulty in that cardboard, cork,

-and like organic cushioning substances deteriorate chemically and physically at the temperatures requisite for baking. When it is sought to employ spots of liners having a paper base satu rated or coated with a resin composition, the same diiculty arises. For example, white sulte papers do not withstand baking at temperatures in excess of 300 degrees F., which is essentially the minimum baking temperature for the coatings.

It has now been found that a closure facing material of adequate strength and possessing the necessary flexibility for procuring a tight seal even under the pressure conditions often prevailing with bottled or canned beverages, can be made from a glass fabric having d agglatimLof` baked resin. 'W

In the accompanying drawings:

Figure 1 shows a closure lining material employed in a crown seal.

Figure 2 is a sectional view through a. portion of the lining material, on a much larger scale.

In these drawings, the metal crown seal IUis formed as usual with its crimped or iiuted edge.

2 Claims. (Cl. 117-126) and with a recess for receiving a cushion pad II of cork or like substance, upon which is mounted a lining material in the form of a spot I2. It is preferred to secure the pad II in position by a cement, and to mount the spot I2 upon the pad I I by a thermo-adhesive material.

The lining onstructed as shown in Fig. 2 of a ass fabric aving a sealing coating of the thermo-s res n which provides continuous surfaces at both faces of the fabric and is shown in Fig. 2 as a. coating Il.

'I'he glass fabric may be formed ofihreadsgh C. 9 B.m rsllls.a..b.uadle .efmamentsfeaspunslass. the individual-lamentsliaving a diameter of the ordenotoneatothreetenethousandthanianlich with thirty or forty such iilaments forming a bundle. These filaments are preferably not tightly twisted or spun in providing the bundle, as it is desirable to leave essentially longitudinally eggtgndingwgrevices into which the varnish may enter during the coating operation, to assure 4a thorough permeation of the varnish inte the interstices oi the threads. In this respect, the glass fabric diners from paper in which the bers are individually intermeshed or felted, and in which the varnish can operate by penetration into the pores of the individual bers. The glass cloth should have a. close weave, so that there are essentially no pores visible from side to side of the uncoated material.

Appropriate coating materials are oleoresinous varnishes and enamels, thermosetting phenol-aldehyde 100 percent resin enamels, vinyl resin lacquers (such as polyvinyl chloride and the mixed polymers and interpolyrners from vinyl chloride and vinyl acetate and containing or more percent of the vinyl chloride), and the combinations of such vinyl halide and halide ester polymer lacquers with thermoplastic or thermosetting phenol-aldehyde resins. When employing phenol-aidehyde and vinyl resin lacquers, it is preferred to include a plasticizer to assure exibility. Such lacquers and enamels are preferably dissolved in a suitable solvent such as ketones, esters, or mixtures of the same (such as methyl-isobutyl ketone, isophorone, cellosolve esters, etc.), usually with the addition of diluent hydrocarbons (such as toluol and Xylol). The resin-base material is employed in proportion to the solvent to provide a viscosity which will deposit a sufiicient thickness of the coating composition to provide a desired amount of resin after elimination of the solvent. It is notable that oleoresinous varnishes can be employed for forming surfaces having desirable navor and strength characteristics, since sucn varnishes are customarily regarded as requiring too great a baking tempe'ruregfor such employment.

The 'glass fabric may advantageously have a thickness of two to four thousandths of an inch, and the resin deposit is such as to give a total thickness to the finished material of about three to five thousandths of an inch.

The resin coating composition is applied by brushing, spraying or roller-coating, care being taken to assure a thorough saturation and permeation.

Following coating, the cloth is subjected to drying and baking operations, at a temperature of 375 degrees F. or higher, being the temperature required for baking the lacquer base in order to give it the necessary characteristics of strength and resistance to action from or upon the liquid (such as aqueous solutions and suspensions) to be packaged in the container.

It may be pointed out that when it is sought to employ paper as a base for lining material, baking operations at temperatures exceeding 300 to 350 degrees F. cause charring or decomposition of the base, and even lower temperatures cause the paper to lose combined moisture. In some baking operations, this moisture is lost at varying temperatures of baking, and causes serious damage to the coating material in causing the formation of pores through which permeation may occur, and in seriously degrading the strength of the coating material. The charring and decomposition of the paper itself prevents the bers of the paper from serving as a reinforcement to the coating, and attempts to make liner facing material in this fashion, by use of temperatures high enough (400 to 450 degrees F. or higher) to assure optimum strength and flavor characteristics have led to the degradation of the structure so that it is too brittle to provide liners which are resistant against the deformations occurring while cutting, seating `and sealing crown closures: for example, the strength of the customary uncoated drab express paper averages around 20 to 30 pounds under the Mullen test for bursting strength, and when varnished the strength averages around 30 to 45 pounds, as compared with over 160 pounds with the present material.

The material formed in the manner herein described does not crack or fracture during the operation of cutting the liner material into a spot .or other facing, during operations of assembly while closing the container. Furthermore, the baking of the lining at a high temperature permits the employment of thermo-adhesive materials in securing the spot in place, without change or degradation in the spot material since it has already been subjected to a higher temperature during manufacture.

A further advantage of employment of glass as a base, is that it is capable of withstanding temperatures at least as high as the thermodecomposition and combustion points of such resin coatings, without serious damage to itself, and it does not develop productsvupon heating in contact with the selected resin which are catalysts for provoking decomposition of lacquer coatings such as vinyl ester-halide polymers. The glass itself has no flavor characteristic, and hence it does not have deleterious consequences such as arise in employment of charred or thermo-decomposed cellulose fibers.

As a specific example of practice, a glass ber cloth having a thickness of 2.5 thousandths of -...tially" from a thermcfusible o1' non-heat-hardening phenol-aldehyde resin (100 pounds of Bakelite BR254 which had been cooked at 350 degrees F. with China-wood oil (100 pounds) for three hours until an interassociation of the resin and oil had been produced to form an oleoresinous base together with a limited polymerization of the oil but without jelling of the mixture. This was thinned with a mixture of pounds of isophorone, 80 pounds of vinyl polymer resin (VYHS- a copolymerized 87% vinyl chloride, 13% vinyl acetate resin), dissolved in 96 pounds of isophorone and 224 pounds of xylol. This vinyl solution was mixed with 50 pounds of the oleoresinous solution. The mixture was thinned to approximately seven to ten seconds viscosity (#4 Ford cup test) with methyl ethyl ketone. A coating was applied to the fiber cloth by dipping, and the cloth was allowed to drain and air-dry for ten minutes. Baking was accomplished at 350 degrees F. for nine minutes of final bake. A second coating was similarly applied, drained and air-dried, and then baked at 375 degrees F. for eleven minutes of final bake. The Mullen burstlng strength was in excess of 160 poundsthe limit of the tester. On crowning tests no evidence of cracking around the sealing area was observed.

In a further example of practice, a glass fiber cloth having a thickness of 3.5 thousandths of an inch was coated with an enamel prepared by cooking 100 pounds of a non-heat-hardening phenol-aldehyde resin with 100 pounds of Chinawood oil at 450 degrees for one hour until the oleoresin strings from a hot paddle, thinning with 300 pounds of high-flash naphtha, and then further thinning with toluol to approximately seven to ten seconds viscosity on the #4 Ford cup test. Application was by single-coat dipping, followed by draining and air-drying as before.

The material was baked at 400 degrees F. for 13 minutes at peak or final bake. The Mullen test here also showed the strength to exceed the limit of the tester. The product showed no evidence of cracking around the sealing area during crowning test. The product was not so exible as that of the above example, partly by reason of the greater base thickness of glass ber and partly by reason of the lesser flexibility of the coating material.

It has been found that by this procedure it is possible to prepare closure lining materials having a continuous surface and being essentially water-impermeable, and having the characteristics of being exible, free of flavor characteristics and having adequate bursting and tensile strengths, and thus amply suflicient and satisfactory for crown seal spots, closure disks for screw caps, lock-type and Newman closures, etc.

It is obvious that the invention is not limited to the form of employment described and shown, but may be practiced in many ways within the scope of the appended claims.

I claim:

1. A closure liner facing material for employment upon a resiliently yieldable base, comprising fabric consisting of multiplefinter-woizen fine nhersagganci having a thioknesspf substanf ariinh, andcoatirrgJ adherent to the bers of the fabric and providing a. continuous surface, the material of said coating being the residue produced by baking at a temperature o! substantially 375 degrees F. an enamel prepared by eecting limited polymerization of an inch was coated with a clear enamel prepared 75 substantially 100 parts by weight of China-wood Search Room tially'toff thousandths of an inch, and a coating of water-impermeable resinous material consisting in major part of an oleo-resinous base formed of heat-polymerizable lnterassociated drying oil and non-heat-hardening phenol-aldehyde resin and for the residue consisting of vinyl halide and vinyl acetate polymer resin, which has been baked at a temperature exceeding 350 degrees F. and is adherent to the fibers of the fabric and provides a continuous surface, said facing material being characterized in being exible, free of flavor characteristics, and having a high tensile strength.

EDWARD C. PFEFFER, Jil.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,867,637 Warth July 19, 1922 1,956,481 Warth Apr. 24, 1934 2,013,119 Warth Sept. 3, 1935 2,132,702 Simpson Oct. 11, 1938 2,138,439 Worth Nov. 29, 1938 2,138,882 Robie Dec. 6, 1938 2,195,191 Schmidt Mar. 26, 1940 2,204,859 Hyatt et al. June 18, 1940 2,219,054 Palm et al Oct. 22, 1940 2,238,681 Dorough Apr. 15, 1941 2,259,496 Soday Oct. 21, 1941 2,333,535 Lauer Nov. 2, 1943 2,412,592 Maier Dec. 17, 1946 FOREIGN PATENTS Number Country Date 844,748 France 1939 

